G-Class is in class of its own

This undated image made available by Mercedes-Benz shows the 2013 G63 AMG. (AP Photo/Mercedes-Benz)

It's easy to look down on Toyota Prius drivers — if you're driving the newest and most special Mercedes-Benz G-Class sport utility vehicle.

The unusual-looking G63 AMG, which includes modest design changes made on all G-Class models plus more luxury touches and a more powerful V-8, puts passengers at such seat heights that they tower over minivans, most pickup trucks and, yes, Priuses though gas mileage is another matter entirely.

If the test drive was any indication, plenty of Prius drivers speed up to try to keep the tall, boxy G-Class from getting in front of them in traffic and blocking their views.

Alas, the Priuses, ubiquitous on some California thoroughfares, are no match for the attention-grabbing, powerful G-Class.

Even the old Hummer SUVs that fuel-conscious drivers loved to hate years ago didn't have the awesome 544 horsepower and whopping 560 foot-pounds of torque that come with the top-of-the-line G63 AMG.

This translates into a federal government fuel economy rating of 12 miles per gallon in city driving and 14 mpg on the highway, though the test G63 AMG managed just 10 mpg in city driving and 12.1 mpg in mixed city/highway travel.

With just 1,330 sold in the United States last year, the swaggering G-Class vehicles are not seen much on our roads. But their road presence, the intoxicating exhaust sounds of the biturbo V-8 in the 2013 AMG and the sumptuous alcantara- and leather-clad interior make these vehicles unforgettable.

They rank as the highest-priced SUVs from Mercedes. The base, 2013 G550 with 388-horsepower V-8 has a starting manufacturer's suggested retail price, including destination charge, of $113,905. The starting retail price for a 2013 Mercedes G63 AMG is $135,205.

Competitors include the 2013 Porsche's Cayenne SUV, which has a starting retail price of $50,575 with 300-horsepower, six-cylinder engine and goes to $146,975 for a Cayenne Turbo S with 550-horsepower, twin turbo V-8. Note that the 2013 Cayenne S Turbo is rated by the federal government at 15/22 mpg.

Another competitor in the high-end, high-power, luxury SUV segment is the 2013 Lexus LX, which has a starting MSRP, including destination charge, of $82.425 with 383-horsepower, naturally aspirated V-8. Government fuel ratings for the LX are 12/17 mpg.

But where the Cayenne and LX look like the more mainstream SUVs on today's roads, the G-Class retains an old, utilitarian and quirky appearance.

The G-Class isn't rounded and aerodynamic, for example. It has upright side windows and an upright windshield that with a small amount of glass area, comparatively. The metal pillars at the sides of the windshield are much narrower than those in other SUVs, so they don't block views the way they do in other SUVs. But the upright side windows also mean it can take some getting used to seeing reflections of the driver, passengers and dashboard appear on the side window glass in certain daylight and at night.

There is a big climb up to get inside, so the test G63 AMG's side rails, set next to the pretty, shiny and illuminated door sills, got lots of use, as did the big handles at each doorway.

Each of the leather-trimmed front seats had more than eight controls, including bolster and lumbar controls, to make them eminently comfortable.

Passengers sit upright, in chair-like fashion, so front-seat legroom is an amazing 52.5 inches. Back-seat cushions were shorter than expected, but there was good support, a nearly flat floor and 41.9 inches of legroom.

The G-Class does not offer third-row seating. And, despite the fact the test G63 AMG topped out at more than $137.000, it did not include rear-seat entertainment.

The G63 AMG had awesome engine sounds that were readily heard inside the passenger compartment because dual tailpipes — two on the left side of the vehicle and two more on the right — protruded from just below the step rails at the back of the rear doors. These side exhausts were shiny silver-colored and provided a race-car look that's not expected on an SUV.

The big, 5.5-liter, double overhead cam, biturbo V-8 bristled with power and came to life quickly. But this V-8 also managed slower, city traffic well without requiring the driver to tap the brake pedal often.

The 25.4-gallon gasoline tank didn't take long to empty, however, and premium is required. There is a 5.3-gallon reserve tank as well.

The seven-speed tranny shifted smoothly in leisurely travel. Upshifts were noticeable during aggressive driving, and the driver can select sport mode, manual without a clutch pedal or eco, which automatically shut down the engine at stoplights to save fuel.

With 20-inch wheels and wide tires, the test G63 AMG transmitted vibrations and impacts sizable potholes to the passenger compartment.

The G-Class is, after all, a capable and durable off-roader, with a healthy amount of ground clearance, three differential locks and a low range transfer case for rugged terrain.

Four-wheel drive is always engaged.

A couple items surprised, though. The rearview camera did not include graphic lines on the display screen showing where the vehicle was being steered. And the driver's window did not have automatic power up capability.